"The Intel Atom processor line is associated with low power usage in devices such as a netbook or nettop computer. The emphasis is definitely not on performance, it's on pushing up battery life on a device with a small display and mid-range graphics requirements while still managing a decent desktop experience. Microsoft thinks Atom can do more, though, and wants to use it in servers. With that in mind it is calling on Intel to up the cores in an Atom chip to 16, and deploying it as a low power server chip solution."

Ok, so Dell Fortuna does not use a multicore chip, but the entire Via Nano based server is about the same size as a 3.5" harddrive, meaning they can fit 12 of them in a 2U chassi, and pretty damn powerefficient aswell (20-29 Watts at full use per server).
Sure a multicore chip may be even better, but what I mean is that a chip of Atom/Nano caliber is already used in servers today, and has been for almost two years, and with their low voltage/small size you can fit alot of them in the same physical space as one "regular" server.